...You highlight a point that is dear to my heart. You need a great amount...a very great amount...of confidence in a strategy in order to trade it. A lot of people, perhaps mostly newbies(?) underestimate that. That core need for confidence is one of the foundations of my own plan.
In my opinion, you don't sound ready to trade this system. At least not yet...not until you've built well-founded confidence in it.
Re: Alan Hull...all I know is, (a) his books disclose the methods of his newsletters very clearly, and (b) he is easily contactable. Personally, there are a couple of aspects of his systems (thinking back to Active Investing - I haven't read, "Invest My Way") that require a certain amount of discretion that I can't come at. But he is much more clear about his rules than so many authors.
It would not be difficult to either (a) code his stuff up yourself or (b) hire a system coder to test for you the quantitative aspects of Hull's systems(s) on whichever markets you choose. That's where I'd start, anyway. I can think of at least two "hire an Amibroker coder" services off top of my head; you'd just need to google it. A few hundred (no idea) dollars spent testing the system(s) on the markets / timeframes of choice would be a bargain. If they don't stand up to your requirements on a rules-based basis, then you wouldn't trade it (as you'd then be punting that you are awesome at the discretionary bits).
Regardless of that, your question is fine...hopefully someone here who has subscribed for a while will let you know of their experience. Hull has been around a good while now, so there must be some ASFers that have been members.